Inflatable sole for shoe

ABSTRACT

An inflatable insole includes a hand-operated pump removably attached to the aft end of the insole above the heel and a bleed valve located just below the pump. The pump and the valve are used to adjust air pressure in the insole so the comfort of the shoe can be adjusted according to user preference as well as according to terrain and use of the shoe. The insole is removably attached to the shoe so the insole can be used on other shoes, such as a sandal or the like. The valve can be manually adjustable as well as automatically adjustable.

TECHNICAL FIELD OF THE INVENTION

The present invention relates to the general art of footwear, and to the particular field of customized footwear.

BACKGROUND OF THE INVENTION

Footwear, especially athletic footwear, must provide stable and comfortable support for the body while subject to various types of stress. It is important that a shoe be comfortable and provide support during various foot movements, especially those movements associated with athletic activity which can be high impact movements.

Articles of footwear typically include an upper and a sole, and are sold in a variety of sizes according to the length and width of the foot. However, even feet of similar length do not have the same geometry. Still further, an individual may subject his feet to a wider variety of situations, even while wearing the same shoe. Therefore, a conventional upper should be adjustable to provide support to various foot contours. Many different products and designs have focused on the need for adjustable upper support. For example, the upper may include an ankle portion which encompasses a portion of the ankle region of the foot and thereby provides support thereto.

In addition, it is well known to adjust the size and fit of a shoe through lacing or through one or more straps reaching across the throat of a typical shoe. With respect to fit and comfort, lacing alone suffers from several disadvantages, for example, when the shoe laces or strap is drawn too tightly, the fastening system can cause pressure on the instep of the foot. It is observed that lacing that is comfortable for one situation may be uncomfortable for other situations. Such localized pressure is uncomfortable to the wearer and can make it difficult for the shoe to be worn for prolonged periods of time. Furthermore, while lacing allows the upper of the shoe to be adjustable to accommodate varying foot and ankle configurations, it does not mold the shoe to the contour of individual feet. Moreover, there are areas of the foot which are not supported by the upper, due to the irregular contour of the foot. The ski boot industry has often resorted to using inflatable insertable devices to improve the fit of the boots without the pressure caused by lacing.

One of the problems associated with shoes has always been striking a balance between support and cushioning. Throughout the course of an average day, the feet and legs of an individual are subjected to substantial impact forces. Running, jumping, walking and even standing exert forces upon the feet and legs of an individual which can lead to soreness, fatigue, and injury. These problems are exacerbated if the individual participates in a variety of activities, each of which places its own form of stress on the individual's feet. This is still further exacerbated if the activities are associated with a variety of terrains.

The human foot is a complex and remarkable piece of machinery, capable of withstanding and dissipating many impact forces. The natural padding of fat at the heel and forefoot, as well as the flexibility of the arch, help to cushion the foot. An athlete's stride is partly the result of energy which is stored in the flexible tissues of the foot. For example, during a typical walking or running stride, the achilles tendon and the arch stretch and contract, storing energy in the tendons and ligaments. When the restrictive pressure on these elements is released, the stored energy is also released, thereby reducing the burden which must be assumed by the muscles.

Although the human foot possesses natural cushioning and rebounding characteristics, the foot alone is incapable of effectively overcoming many of the forces encountered during athletic activity. Unless an individual is wearing shoes which provide proper cushioning and support, the soreness and fatigue associated with athletic activity is more acute, and its onset accelerated. This results in discomfort for the wearer which diminishes the incentive for further athletic activity. Equally important, inadequately cushioned footwear can lead to injuries such as blisters, muscle, tendon and ligament damage, and bone stress fractures. Improper footwear can also lead to other ailments, including back pain.

In light of the above, numerous attempts have been made over the years to incorporate into a shoe a means for providing improved cushioning and resiliency to the shoe.

A shoe generally consists of two basic parts, an upper and a sole. The upper is generally designed to enclose and provide cushioning to the foot. The upper also typically includes an insole to provide initial support and cushioning to the bottom of the foot. The upper is attached to a sole which provides additional protection and cushioning primarily to the bottom of the foot. The sole also imparts stability to the shoe.

The increase in demand for shoes for sports and outdoor activities such as walking, running, hiking, tennis, basketball and numerous other high activity sports has prompted many advances in shoe design to provide improved protection and comfort to the feet, ankles, legs, hips, etc. Efforts to improve shoes have centered on decreasing shoe weight and improving cushioning, flexibility, and stability. In addition, shoe soles are desired with improved memory, shock dispersion capabilities and energy return.

The effort to design improved shoes has prompted increased study of foot dynamics in general and the study of foot dynamics as it relates to particular activities such as running, basketball and other specific activities. The combination of research and research-responsive shoe design has resulted in shoes designed for specific activities. For example, the pressures exerted by a foot on a sole when walking are different from the pressures exerted by a foot when running, or when playing tennis, etc. Accordingly, the modern sport shoe design takes into account the specific requirements of shoes used for particular activities. In addition, modern sport shoe design attempts to take into account the specific needs of the individual, such as weight, foot width and other individual characteristics such as pronation and supination. Thus, general considerations such as shoe weight, cushioning, flexibility and stability are taken into account in designing sport shoes for particular activities and individual needs. Although the functional characteristics of the shoe are of primary importance, other factors such as cost, appearance of the shoe and ease of use must be taken into account for full consumer satisfaction.

Sport shoe refinements have concentrated particularly on the sole. Sport shoe soles typically have two components, the midsole and the outsole. The outsole is the ground-contacting portion of the sole and provides traction and protection to the remainder of the sole. Outsoles, accordingly, are composed of durable materials, such as rubber, which provide both traction and high abrasion resistance. The midsole contributes to foot stability and is the primary shock absorption member of the sole. The midsole is composed generally of a softer, more flexible material than the outsole. Since the midsole is important to such factors as stability and shock absorption, the design of the midsole has received considerable attention by sport shoe manufacturers.

Typically, midsole construction centers around plastics expanded into foams which are then shaped in a number of ways to accommodate a shoe upper. The foam midsole is then covered with a more durable sheet of outsole material, usually rubber, to provide the sole with adequate abrasion resistance and traction. Attaching an outsole to a foam midsole is generally a labor-intensive process. For example, attaching a rubber outsole to a midsole requires abrading the surface of the midsole, washing the surface with a solvent, layering both the midsole and outsole surfaces with cement where they are to be joined, then activating the treated surfaces, usually with heat. This is followed by touch-up and decoration processes.

A foam midsole material by itself is generally inadequate to provide the stability and cushioning demanded for modern sport shoes. The foams used in current soles have insufficient external surface tension by themselves to provide the required stabilizing forces in response to pressures exerted on a sole. This is especially true with extremely low density foams employed to minimize weight. Moreover, current foam midsoles quickly lose their ability to adequately cushion, often after as little as 20% of the shoe life.

The problems of stability and cushioning associated with the use of foam midsoles has prompted several approaches for increasing stability and prolonging the cushioning properties of midsoles. Efforts to improve stability have centered on the use of inserts of denser, more rigid materials than the main midsole component, such as dense foam plugs or solid thermoplastic inserts. These are either inserted directly into the foam midsole component before curing or cemented into place afterwards in another labor-intensive process. Efforts to improve cushioning while maintaining adequate stability have centered on the use of flexible thermoplastic inserts and liquid or gas filled inserts. These inserts also are generally encapsulated in the main midsole component. Thus, modern sole design has centered on constructing soles having varying degrees of flexibility in selected areas of the sole. For example, inserts can include foamed plugs of material harder or softer than the main midsole component. As stated, the inserts are typically encapsulated in the midsole material to provide areas in the midsole of lesser flexibility where increased stability is desired, and areas of greater flexibility where increased cushioning is desired. Other approaches include the use of resilient spheres embedded in the midsole by casting or injection molding the midsole around the spheres. Trampoline devices incorporated into the heel region of shoes have been attempted, but cost and appearance factors have limited the use of this concept. Various gels and gases have also been incorporated into midsoles in an attempt to enhance and prolong cushioning and energy return. However, soles incorporating gels or gases such as air are costly to manufacture and relatively unpredictable in their functional characteristics.

Midsoles have also been constructed of a shell of a thermoplastic elastomer designed to encapsulate and protect low density synthetic foams such as polyether, polyurethane or polyester polyurethane. Increased rigidity along the periphery of the sole is provided by convolutions in the shell material along the edge of the sole. Plugs of denser foam are still incorporated into the main foam component where more rigidity in the inner foam component is desired. Moreover, such shells are generally made by blow molding the thermoplastic material. Blow molding involves costly molds, which limit the size and number of design changes. Additionally mold costs become a significant factor when the number of shoe sizes for each shoe model is taken into account. This is reflected in higher sole unit costs. Thus, shoes manufactured by blow molding techniques are limited to higher priced shoes although the gain in performance over traditional sport shoes employing foam midsoles is not particularly significant since the interior of the shell sole is still composed of foam which breaks down and loses its cushioning effect in a relatively short period of time. Because of the cost involved in manufacturing such soles, their use has been limited primarily to heel components. Accordingly, shoe sole components are desired having improved performance and cost effectiveness.

Still further, people often own several different shoes, each of which can be used for one or more situations. To be most comfortable, all shoes owned by a person should be as comfortable as possible in any situation. However, if each shoe is specifically designed for a particular use, the shoes may be too expensive and may even require several of the same type of shoes, each of which is designed for a different wearing situation. Therefore, there is a need for a device that can be adapted for use with a variety of shoes and which will make each shoe as comfortable as possible for the particular wearing situation.

Presently available shoes have several problems. For example, one of these problems is that often fluid filled devices are not adjustable for physiological variances between people and the variety of activities for which athletic shoes are warn. It has been known to adjust fluids in the sole of footwear. However, under foot devices, while providing cushioning to the sole, typically do not aid in support for the sides, top and back of the foot. Attempts to cushion the upper and sole of a shoe with air have resulted in products that are either ineffective or, because of the construction techniques used, are too heavy and cumbersome to be used for a running shoe.

Furthermore, in some underfoot cushioning systems, when the heel contacts the ground during the gait cycle, fluid is transferred from the heel area of the foot and displaced to the forefoot area of the foot, causing the pressure in the forefoot area to increase. Because the underfoot portion of an inflatable bladder is typically separate from the portions of an inflatable bladder along the sides and top of the foot, downward pressure in the heel of a conventional cushioning device has no effect on the cushioning surrounding the sides and heel of a foot.

Inflatable shoe inserts known to the inventor are generally designed to be used in conjunction with a conventional shoe upper. A shoe with this type of design can be quite expensive because it requires all the materials of the upper and the additional materials of the inflatable insert. Often the inflatable inserts also add bulk to the shoe because they require a system of complex tubing between the inflation mechanism and the inflatable bladder. With the present of an upper to completely surround the foot, there is no need for the inflation inserts to completely surround the foot. Many inserts may only support certain regions of the foot.

Most inflatable shoes include either a hand-held inflation mechanism, or an on-board inflation mechanism which is used to selectively inflate only a portion of a shoe. Other inflatable shoes are pre-inflated at the factory. Whether inflated at the factory or inflated by the user, there is a problem with diffusion of air out of the shoe. In the case of shoes inflated at the factory, the problem of diffusion has been partially solved by utilizing a large molecule gas as the fluid for inflating the shoe. While the large molecule gas does not diffuse at the same rate as air, the gas is more expensive which increases the costs of the shoe, and a user is not capable of varying the amount of pressure in the shoe to his individual preferences.

None of the devices known to the inventor provides a simple, inexpensive, versatile solution to comfortable wear and walking in a wide variety of footwear. Foam inner soles have only a limited value and limited shock absorbency and other devices, including a pressurization system for ski boots, are relatively complex and costly and are often too bulky and cumbersome. Consequently, these devices are not readily acceptable for everyday activities.

SUMMARY OF THE INVENTION

The above-discussed disadvantages of the prior art are overcome by an inflatable insole with a hand-operated pump removably attached to the aft end of the insole above the heel and a bleed valve located just below the pump. The pump and the valve are used to adjust air pressure in the insole so the comfort of the shoe can be adjusted according to user preference as well as according to terrain and use of the shoe. The insole is removably attached to the shoe so the insole can be used on other shoes, such as a sandal or the like. The valve can be manually adjustable as well as automatically adjustable.

Using the embodying the present invention will permit an individual to have a single insole that can be used on a variety of different shoes and which can be adjusted according to use for maximum comfort. The pump and valve are located in an easily accessible location so the insole can be easily modified according to the particular situation.

Other systems, methods, features, and advantages of the invention will be, or will become, apparent to one with skill in the art upon examination of the following figures and detailed description. It is intended that all such additional systems, methods, features, and advantages be included within this description, be within the scope of the invention, and be protected by the following claims.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

The invention can be better understood with reference to the following drawings and description. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. Moreover, in the figures, like referenced numerals designate corresponding parts throughout the different views.

FIG. 1 is a perspective view of a shoe having an inflatable insole embodying the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Referring to the figure, it can be understood that the present invention is embodied in a shoe 10 which comprises an outer sole 12 which will contact a support surface, such as a sidewalk or the like and an upper section 14 which encases a wearer's foot when in use. The outer sole and the upper section can be formed of materials common to wearing apparel.

An inner sole 16 is located superadjacent to the outer sole and is releasably attached to the upper section and is also releasably attached to the outer sole. The inner sole is interposed between the upper section and the outer sole. The inner sole is flexible and inflatable and is designed to contain fluid, such as air and to maintain that fluid in the inner sole when a wearer walks on the inner sole. Those skilled in the shoe art will understand what sort of material will be suitable for the inner sole based on the teaching of the present disclosure.

A fastener unit 20, such as a hook-and-loop fastener unit, releasably attaches the inner sole to the outer sole and to the upper section as indicated in the figure. If the wearer decides to change shoes, he or she needs only to remove the inner sole from the outer sole by releasing the fastener unit and then re-attaching the inner sole to a new shoe. In this manner, the inner sole 16 can be used in a wide variety of situations and with a wide variety of shoe styles.

A toe section 30 is located on the front end of the shoe and a heel section 32 is located on the aft end of the shoe.

An inlet valve unit 40 is mounted on the heel section and is fluidically connected to the inner sole, and a pump 42 is fluidically connected to the inlet valve to pump fluid, such as air, into the inner sole when activate, as by hand manipulation of a flexible bulb or the like. In one form of the invention, the pump is releasably mounted on the upper section at the heel section, while in a second form of the invention, the pump is permanently mounted on the upper section at the heel section.

A pressure release valve 46 is fluidically connected to the inner sole and is located subadjacent to the pump. The pressure release valve can be set either manually or can be automatic to maintain the fluid pressure in the inner sole at a level that is desired and comfortable for the particular use being made of the shoe. In this manner, the comfort of the shoe can be customized for the particular application being made of the shoe by the wearer.

Use of shoe 10 can be understood from the foregoing, and thus will be only briefly reviewed. A wearer selects the particular upper section he or she wishes to wear, then attaches the inner sole to that upper section and then attaches an outer sole to the inner sole. The wearer then inflates the inner sole to the level desired for the particular use he or she will make of the shoe. The inflation is achieved using the pump and the pressure release valve. The pump can be removed in one form of the invention and will remain attached in place in a second form of the invention. In any event, the location of the pump on the aft end of the shoe allows a user to inflate the sole without removing the shoe and while maintaining his foot in a comfortable position.

While various embodiments of the invention have been described, it will be apparent to those of ordinary skill in the art that many more embodiments and implementations are possible within the scope of this invention. Accordingly, the invention is not to be restricted except in light of the attached claims and their equivalents. 

1. A shoe comprising: A) an outer sole; B) an upper section, the upper section encasing a wearer's foot when in use; C) an inner sole that is located superadjacent to the outer sole, the inner sole being releasably attached to the upper section and releasably attached to the outer sole and interposed between the upper section and the outer sole, the inner sole being flexible and inflatable; D) hook-and-loop fastener releasably attaching the inner sole to the outer sole and to the upper section; E) a toe section; F) a heel section; G) an inlet valve unit mounted on the heel section and fluidically connected to the inner sole; H) a pump fluidically connected to the inlet valve, the pump being releasably mounted on the upper section at the heel section; and I) a pressure release valve fluidically connected to the inner sole and located subadjacent to the pump.
 2. A shoe comprising: A) an upper section; B) an outer sole; C) an inner sole interposed between the upper section and the outer sole, the inner sole being inflatable; D) a fastener unit releasably attaching the inner sole to the upper section and to the outer sole; E) a fluid inlet valve mounted on the upper section and fluidically connected to the inner sole; F) a fluid pump mounted on the upper section and fluidically connected to the fluid inlet valve; and G) a pressure release valve mounted on the upper section and fluidically connected to the inner sole.
 3. The shoe according to claim 2, where the fluid pump is releasable from the upper section of the shoe. 